Braking system



Oct. 19, 1937. c. D. STEWART BRAKING SYSTEM Filed Feb. 1, 1936 RELEASEMERGENCY ICE INVENTOR CYLINDER BRAKE CARLTEIN I]. STEWART M 6M ATTORNEYPatented Get. 19, 1937 Y UNITED STATES PATENT OFF'lCE BRAKING SYSTEMCarlton D. Stewart, Swissvale, Pa., assignor to The Westinghouse AirBrake Company, Wilmerding, Pa., a corporation of PennsylvaniaApplication February 1, 1936, Serial No. 61,929

Claims. (01. 303-3) This invention relates to braking systems, and A yetfurther object of the invention is to prom-ore particularly to brakingsystems for traction vide a combined fluid pressure and magneticvehicles and railway trains employing both fluid track brake equipment,in which the magnetic pressure brakes: and magnetic track brakes. trackbrake will be cut out of action at a low 5 In the design and manufactureof certain types brake cylinder pressure. In this manner the 5 of moderntraction and railway vehicles rubber magnetic track brake devices may bedeenergized inserts are placed between. the wheel treads and during thetime the vehicle is held at rest, where the wheel hubs in order toproduce quiet operonly a low brake cylinder pressure is required.

. ation. Where such rubber inserts are employed A still further objectof the invention is to prothe degree of braking which may be produced onvide a combined fluid pressure and magnetic 10 the wheel treads islimited, because if the wheel brake equipment,in which applications ofboth treads are permitted to become overheated the types of brakes maybe effected either by straight rubber inserts may be wholly destroyed ordamair operation or by automatic operation, straight aged beyondusefulness. Since the degree "of air operation being employed for normalservice braking on the wheel treads must be thus limited, applicationsand automatic operationbeing em- 15 other brake means'mustbe emp-loyedto produce ployed for emergency applications. suficient braking to stopthe vehicle in a reason- Other objects and advantages of the invention,ably short-distance. dealing with specific constructions and arrange Adesirable type of auxiliary brake means to ments of parts, will be morefully understood from employ is a magnetic track brake. As is well thefollowing description, which is taken in con- 20 known, this type ofbrakeemploys one or more nection with the attached drawing, whereinmagnetic track brake devices which, in. their in- Fig. 1 shows inschematic and diagrammatic operative or release. position, are normallysusform one embodiment of thei'nvention adapted pended above the trackrails and caused to engage for a single vehicle, and

the rails in their application position, to produce a Fig. 2 illustratesin diagrammatic form combraking effect on the track rails. At, orslightly munications established by the: brake valve debefore, the timeof engagement with the track vice shown to the upper left in Fig. 1.rails the track brake devices are energized, so that Referring now tothe drawing, the fluid presthe track braking is produced solely as aresult sure brake system may comprise one or more 00i the magneticattraction. between the track brake cylinders ill, a brake valve deviceii, an

brake devices and the rails. emergency valve device 12, and a mainreser- Where a magnetic track brakesis used in convoir l3. 7 junctionwith a shoe-on-wheel type of brake, as The magnetic track brake systemmay comprise for example the fluid pressureoperated shoe-onone or moremagnetic track brake devices M, a wheel brake, it is desirable thatmeans be prolike number of raising cylinders l5, a magnet vided wherebythe degree of application of each valve device IS, a fluid pressureoperated switch of these brakes may be controlled conjointly in deviceI1, and a fluid pressure operated rheostat response to the manipulationof a single control device l8. handle. At theflsame time, it isundesirable to Considering now these devices more in detail, permit thefluid pressure brakes to be applied to the brake valve device I I may beone of a number 40 a degree such that the rubber inserts in the oftypes, and I have by way of illustration shown wheels would be damaged.a rotary valve type embodied in a casing having a It is aprincipalobject of the present invention chamber 20 in whichv isdisposed a rotary valve 2| to provide a combined fluid pressure andtrack operated by a handle 22. The chamber 20 is in brake equipment inwhich the degree of applicaopen communication with the main reservoir I345 tion of each brake is contro-lledaccordingf to, and by way of pipeand passage 23. v in response to, manipulation of a single control Whenthe handle 22 is in release position, a element. i cavity 24 establishescommunication between a A further object of the present invention is tostraight air pipe 25 and exhaust port 26, as is provide a combined brakesystem of the type diagrammatically shown in Fig. 2. Also in release 5above referred to, in which control of the lowering position of thehandle 22, an emergency pipe 21 -of the'track brake devices intoengagement with is connected to chamber 20, by a port 28 in thetheztrackrail, and the degree of energization rotary valve 2|. thereof,are controlled according to brake cyl In lapposition of the handle22,.the straight air 'inder pr s re. i I I .pipe 25 is disconnected fromthe exhaust port 26, 55

to be operated by and coextensive with movement.

of a piston 33 operatively mounted in the piston chamber 30. stem 34having collars 35 thereonzi'or engaging the slide valve 32. A spring .36urges the piston 33 to its extreme right hand position, Where it comesto rest against stops 31,. t

The slide valve chamber 3| is in communica tion with the main reservoirl3 by way of main reservoir pipe 38 and branch pipe 39. The pistonchamber 30 is in communication with the emergency pipe 21. When thepiston 33'is in the position as illustrated in Fig. 1, the pistonchamber 39 is in restricted communication with the slide valve chamber3| by way of feed groove 40;

The magnetic track brake device |'4 may be of any of the types commonlyemployed. This track brake device may have attached thereto a bracket 4|which is connected to a stem 42 of .piston43 disposed in chamber 44 ofthe raising cylinder l5.

Chamber 44 is connected by 'a pipe 45 to the magnet valve device |6.,

The magnet valve device I6 is embodied in a casing provided with adouble beativalve 45,

' which is urged toward upper seated position by posed in a pistonchamber 5|. is urged downwardly by a spring 52 'andis actuated upwardlyupon supply of fluid under'pres- ,sure to the chamber 5|. 'is in itsupper position a bridging contact '53 a springv 4! and to lower seatedposition by' action of an electromagnet (not shown) in the upper part ofthe'casing which when energized actuates double beat valve 46downwardly.

When the double beat valve 46 is in upper seated position the pipe 45 isconnected to main reservoir pipe 38, and when the double'beat valve isin lower'seated position this communication is cut off and pipe 45 isconnected to the atmo phere by way of exhaust port 48.

The fluid, pressure operated switch: device I! is embodied in a casinghaving apiston 50 dis- The piston 50 engages and closes'stationarycontacts 54.; The

chamber 5| is connected by a pipe 55 to straight air pipe 25.

Thefluid'pressure operated rheostat device I8 comprises a rheostat 51,indicated diagrammatically, which isprovided with a movable arm 58adapted to constantly engage a contact segment 59 and to connect thissegment with a plurality of contacts 60, for the purpose of cutting outI portions of a resistance 6|.

The arm 58 is connected by a stem 62 to a piston 63 disposed in chamber64'. A calibrated spring 65 urges the piston .63 to its extreme righthand position. When fluid under pressure is supplied to the chamber 64the piston 63 moves'to the left until the pressure exerted by thepresence of fluid in chamber 64 is balanced by the opposing pressure ofspring 65. V

The partsare so designed that the arm 58 is not actuatedto the positionwhere segment 59 is connected to the first or right hand Contact Thepiston 33 is provided with a 'erated rheostat device I8.

When the piston 56' 60 until a predetermined pressure has beenestablished in chamber 64, as'for example 15 pounds. Thereafter, as thepressure in chamber 64 increases the arm 58 is actuated further in aclockwise direction to. engage other of the contacts 60 to cut outportions ofresistance 6|.

The brake cylinder It! has been shown in mechanical connectionwithbrakeshoes. 5.1; oper- V ating upon the treads of vehicle wheels 68,by

means of levers 69 and brake rod 10, but it is to be understood thatthese means are shown as illustrative only of the many types of brakeriggings employed in practice.

The operation of this embodiment'of my invention is as follows:

When the vehicleis running under power, or

coasting, the parts of the brake equipment will v be in the positionsshown in Fig. 1. As will be observed from this figure, the emergencypipe r 21 is in communication with the main reservoir I3, and-thepressure-exerted on piston 33 inthe emergency valve device I2, both fromthe fluid pressure in piston chamber 30' andirom the spring 36, biasespiston33 to its extreme right hand position. 'At the same time, themagnet valve device I6 is deenergized to. permit thesupply of fluidunder pressure therethrough to the raising cylinder I5, to maintain thetrack brake device |4 suspended above the track rail H.

When it is desired to 'efiecta service applica tion of the brakes,thehandle 22 is turned to the service application position. tion, thestraight air pipe 25 is disconnectedfrom exhaustport 26 and connectedbycavity l2 to the, main reservoir. Fluid underpressure then 1 flowsfrom the mainreservoir to'the straight.

air pipe 25. 'The straight air' pipe is divided In this posiinto twosections, the two sections being connected by cavity 13 in slide valve32 of the emergency valve device |2 solong as the emergency pipe 21 ismaintained charged.

Fluid under pressure in the straight air pipe 25 flows to the brakecylinder l5, .tochamber 5| of the fluid pressure operated switch device.

l1, and to chamber 64 of the'fluid pressure op- When the pressure offluid as for example 15 pounds, the switch device ll will close contacts54, while the fluid pressure operated rheostat device I8 will haveactuated arm 58to connect the right hand contact '69 to thesegment 59. v2 Y Closingof-the contacts 54 energizes'the magnet valve device |6 from'a' suitable source of current supply, as a battery 14. When this valve46 to vent the chamber 44 inraising cylinder l5. The track brake deviceI 4 then drops by gravity to engagement'with the track rail 1|. 4 f

'At the same time, the connection of segment 59 with the right handcontact 60 energizes the track brake device |4 also from the battery 14.The track brake device istherefore applied when the pressure in. thebrake cylinder has reached a predetermined low value. Both' the trackbrakes and the wheel brakes willthus be applied.

As the pressure of fluid supplied to the straight air pipe 25 increases,the rheostat arm 58 will J be actuated further in a clockwise directionto cut out portions of resistanceofil, and thus increase theenergization of the track brake dein the straight air pipe 25 reachessome predeterminedlo'w value, a

device is energized it seats its double beat valve The'brake cylinderpressure willlike wise be increased, so that both the wheel brak- J ingand 'thetrack braking will be increased to a corresponding degree.

When it is desired to effect a release of the brakes following a serviceapplication, the brake valve handle 22 is returned to release position.In this position the straight air pipe 25 is reconnected to exhaust port25 to release fluid under pressure from the brake cylinder l0 and theother devices connected to the straight air pipe 25.

'When the pressure in the straight air pipe 25 diminishes to 15 pounds,the switch device I! will open its contacts 54 and the rheostat devicel8 will disconnect the track brake device Hi from the battery 14.Thereafter, the fluid pressure brakes onlywill remain applied to bringthe vehicle to a stop.

In order to control the degree of application duringa serviceapplication, the brake valve handle 22 is turned to the service positionand left there until the desired pressure has been established in thestraight air pipe 25; Then it is turned to the lap position.

-When it is desired to effect an emergency application of the brakes,the brake valve handle 22 is turned to the emergency position where itis permitted to remain. In this position, the straight air pipe 25is'connected to the main reservoir [3, as before, while in addition theemergency pipe 21 is disconnected from the main reservoir and connectedto the exhaust port 26.

The resulting venting of the emergency pipe 2! reduces the pressure inthe piston chamber 30 of the emergency valve device l2, and theoverbalancing pressure from the slide valve chamber 3| actuates thepiston 33 to its extreme left hand position. In this position of piston33, the slide valve 32 blanks or isolates the left hand section of thestraight air pipe 25, while opening the right hand section of thestraight air pipe to the slide valve chamber 3|. Fluid at main reservoirpressure then flows through pipes 38 and 39 to slide valve chamber 3 I,and from thence through theright hand section of straight air pipe 25 tothe connected devices, until equalization takes place. As will beobvious, both the fluid pressure brakes and the magnetic track brakeswill be applied quickly and to a maximum degree.

It will be noted that although the emergency slide valve 32 blanks theleft hand section of the straight air pipe 25, fluid under pressure willbe supplied to this section through the brake valve device II. If,therefore, for any reason, due to faults or otherwise, the piston 33should accidentally move back to its release position, fluid underpressure would be supplied to the right hand section of the straight airpipe from the 'brake valve device. Thus an application of the brakes isdoubly insured when effecting an emergency application.

To effect a release of the brakes following an emergency application,the brake valve handle 22 is returned to release position. In thisposition, the emergency pipe 21 is again connected to the main reservoirI3, and when the combined pressure of fluid in piston chamber 30 andspring 36 overbalances the pressure in the slide valve chamber 3|,piston 33 will move back to its release position and thus connect thetwo sections of the straight air pipe. The straight air pipe will thenbe vented to the atmosphere through cavity 24 in the brake valve device.

It will thus be seen that in the embodiment of my invention illustratedboth the fluid pressure and magnetic track brakes may be controlled froma single control handle, and that applications may be effected by eitherstraight air operation or by automatic operation.

to this embodiment or otherwise than by the spirit and scope of theappended claims.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a vehicle brake system, in combination, fluid pressure brakemeans, a magnetic track brake device, a pipeto which fluid underpressure is supplied in effecting operation of said fluid pressure brakemeans to supply the brakes, electroresponsive means operable whendeenergized to effect suspension of said track brake device above atrack rail, and when energized to effect engagement of said track brakedevice with said track rail, switch means responsive to a predeterminedlow pressure in said pipe for effecting energizarail, switch meansresponsive to pressure in said pipe for effecting operation of saidelectroresponsive means to cause engagement of said track brake devicewith said track rail, and separately operable current controlling meansalso responsive to the pressure in said pipe for connecting said trackbrake device to a source of current supply at a low pressure and forthereafter varying the current in said track brake device as thepressure in said pipe increases.

3. In a vehicle brake system, in combination, a brake cylinder, amagnetic track brake device, a first circuit for supplying current tosaid track brake device, a resistance in said first circuit, a secondcircuit for controlling raising and lowering of said track brake deviceout of and into engagement with a track rail, said track brake devicebeing raised when said second circuit is open and lowered when saidsecond circuit is closed, a pipe to which fluid under pressure issupplied in effecting a supply of fluid under pressure to said brakecylinder, a switch device responsive to the pressure of fluid in saidpipe for closing said second circuit, and separate fluid pressureoperated means also responsive to the pressure of fluid in said pipe forfirst connecting said first circuit to a source of current supplyand'for then cutting out portions of said resistance.

4. In a vehicle brake system, in combination, a brake cylinder, amagnetic track brake device, a pipe to which fluid under pressure issupplied in effecting a supply of fluid under pressure to said brakecylinder, electroresponsive means for normally causing said track brakedevice to be suspended above a track rail and operative at a lowpressure in said pipe for effecting engagement of said track brakedevice with said rail, current controlling means responsive to a lowpressure in said pipe for connecting said track brake device to a sourceof current supply and for varying the current supplied thereto as thepressure in said pipe increases, manually operated means for effecting asupply of fluid under pressure to said pipe to various degrees, and anautomatic valve device operated upon a decrease in' pressure foreffecting asupply of fluid under pressure to said pipe to a maximumdegree r 5; In a vehicle brake system, in combination, a brake cylinder,a magnetic track brake device,

fluid pressure operated means operated when fluid under pressure issupplied thereto to maintain automatic valve device operated upon adecrease in pressure for closing said communication to said variablesupply and for connecting said communication to a maximum supply,electroresponsive means responsive to a low pressure of fluid suppliedto said communication for-reduc ing the pressure in said fluid pressureoperated means to permit said track brake device to drop to engagementwith the track rail, and current controlling meansalso responsive to alow pres-' sure of fluid supplied to said communication for connectingsaid track brake device to a source of current supply and operable uponan increase of pressure in said communication for increasing the currentsupplied to said track brake device. 6. In a vehicle brake system,incombination, a brake cylinder, a magnetic track brake device,

fluid pressure operated. means operable 'when fluid under pressure issupplied thereto to maintain'said track brake device suspended above atrack rail and operated upon a decrease of pressure therein to permitsaid track brake device to drop by gravity to engagement with the trackrail, a magnet valve device operable when deenergized to effect a supplyof fluid under pressure to said fluid pressure operated means and whenenergized to effect a decrease of pressure in said fluid pressureoperated means, means for effecting a supply of fluid under pressure tosaid brake cylinder, a switch device operated at alow brake cylinderpressure for effecting energization of said magnet valve device, andseparate current controlling means operated at a; low brake cylinderpressure for connecting the track brake device to a source of currentsupply and operable as brake cylinder pressure increases to increase thesupply of current to said track brake device.

'7. In a vehicle brake system, in combination,

a brake cylinder, a magnetic track brake device, means for effecting asupply of fluid under pressure to said brake cylinder, fluid pressureoperated means operated upon an increase in pressure for raising saidtrack brake device from a track rail and operated upon a decrease inpressure for eflecting engagement of said track brake device with thetrack rail, a magnet valve device operable when deenergized to supplyfluid'under pressure'to saidfluid pressure operated means andoperablewhen energized to effect a decrease r of pressure in saidfluidpressureoperated means,

means operated; at brake V-cylinder pressure for energizing said magnetvalve devicefand independently' operated current" controlling'meansoperated at a low brake cylinder pressure for connecting said trackbrake device to 'a source of current supply androperablexas' said brakecylinder pressure increases to increase the supply current to said trackbrake device. a

8. In a vehicle brake system, in combination,

a brake cylinder, a magnetic track brake device, 7,

means for eifecting a supply of fluid under pressure to said brakecylinder, a first circuit for supplying current to said track brakedevice, a resistance'in said circuit, a second circuit operable whenclosed to efiect lowering of said track brake device to engagement witha track rail,

means operated by brake cylinder'pressure for 7 closing said secondcircuit, and separate means also operated by brake, cylinder pressurefor closing'said first circuit and for cutting out p0r'-' tions of saidresistance.

9. In a vehicle brake system,in combination;

a brake cylinder, a magnetic track brake device, a straight airpipetowhich fluid 'under pressure 30 is supplied in efiectinga'supply offluid under pressure to said brake cylinder, abrake'valve' deviceoperable to effect a supply offluidunder Q pressure to saidstraight-airpipe to variable degrees, an automatic valve device operatedupon a decrease in pressure to isolate saicl'rbrake valve device and tosupply fluid under pressure to'said straight air pipe to a maximumdegree, electro responsive means'operated in response to straight airpipe pressure for. effecting engagement of said track brake devicewith'the track rail, and" means operated by straight air pipe pressurefor effecting and controlling the degree of energiza-f tion of saidtrack brake device. 7

10. In a vehicle brake system, in combination, a brake cylinder, amagnetic track brake device, electroresponsive means operable whenenergized to effect lowering of said track brake device to 1 engagementwitha track rail. and when deenergized to reflect raising of said trackbrake device above the track rail, current controlling meansforeffecting and controlling the degree of energization of said trackbrake-device, means for effecting a supply of fluid under pressure tosaid,

brake cylinder, and meansseparate fromzsaid current controlling meansand operable by brake cylinder pressure for effecting energization of I7 said electroresponsive meansland operation-of 7 said currentcontrolling'means'and operable at a predetermined low brake cylinderpressure to effect deenergizationlof said, electroresponsive means andsaid track brakedevice;

CARLTON D. STEWART. Y

Patent No. 2 ,o96,u7u.

CERTIFICATE OF CORRECTION.

Qctober l9, 1957.

CARLTON D. STEWART;

It is hereby eertifieci that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5second opinion," line 1 5, claim 1, for supply" read apply; and that thesaid Letters Patent should be read with this correction therein that thesanemay conform to the reeord of the case in the Patent Office.

Signed and sealed this 18th day of Januar A. D. 1935;.

Henry Van Arsdale (Seal) Acting Commissioner of Patente.

